RE: Sterling RIMFIRE
A friend of mine built one when we were both in the Army 73 or 74 it had a badly warped wing. I witnessed the first flight he was a lot better pilot than I and was able to get it back down in one piece. If I recall he pulled the engine and radio out after the first flight. I think even if the wings had not been warped it would have been a handful very thin airfoil and heavy but with lots of power.
Richard